Thyroid Artery Flow Velocity and Serum Adenosine Deaminase After Methimazole Therapy in Autoimmune Hyperthyroidism

Summary

This protocol aims to assess thyroid vascularity and immune activity in autoimmune hyperthyroidism by integrating Doppler ultrasonography with serum adenosine deaminase (ADA) measurement. It provides a non-invasive approach to evaluate disease severity, monitor therapeutic response, and differentiate Graves’ disease from Hashimoto’s hyperthyroidism with improved clinical accuracy.

Abstract

Autoimmune hyperthyroidism, including Graves’ disease and Hashimoto’s hyperthyroidism, presents with overlapping biochemical features but distinct pathophysiological mechanisms. Non-invasive methods that reflect both vascular and immune activity may improve disease differentiation and treatment monitoring. This retrospective single-center study included 60 newly diagnosed hyperthyroid patients (30 Graves’ disease and 30 Hashimoto’s hyperthyroidism). All participants underwent baseline and 12-week follow-up evaluations after methimazole therapy. Assessments included thyroid function tests, superior thyroid artery Doppler parameters (peak systolic velocity [PSV], resistance index [RI]), and serum adenosine deaminase (ADA) levels. Statistical analyses included paired and independent t-tests and Pearson correlation. At baseline, PSV and ADA levels were higher in Graves’ disease compared to Hashimoto’s hyperthyroidism. After 12 weeks of methimazole treatment, both groups showed significant reductions in PSV and ADA (p < 0.05), with greater changes observed in Graves’ disease. Moderate correlations were observed between ADA levels and Doppler parameters. The combined assessment of Doppler ultrasonography and serum ADA provides a reproducible, non-invasive approach to evaluate vascular and immune changes during therapy. While the method shows potential for differentiating autoimmune hyperthyroid subtypes and monitoring treatment response, further validation in larger cohorts is required.

Introduction

Graves’ disease and Hashimoto’s thyroiditis are the most common reasons for hyperthyroidism globally. Their common immune systems do not explain the wide variety of symptoms and ways they develop in the body^1,2,3. This disease occurs when thyroid-stimulating hormone receptor antibodies cause the thyroid to grow and secrete excessive thyroid hormones. Unlike other thyroid disorders, Hashimoto’s thyroiditis causes the body’s defense cells, cytotoxic T cells, to destroy thyrocytes, contributing to transient hyperthyroidism because of released thyroid hormones in the inflammatory....

Protocol

Ethics Statement

This study was approved by the Institutional Human Research Ethics Committee of Shishi City Hospital (Approval No.: 2026038). Written informed consent was obtained from all participants. All procedures were conducted in accordance with the Declaration of Helsinki.

1. Participant Recruitment and Enrollment

1. Screen Potential Participants
   1. Verify age between 18 and 60 years.
   2. Confirm newly diagnosed hyperthyroidism by suppressed TSH (<0.01 mLU·L^-1) and elevated FT3 and FT4.
2. Classify Partici....

Results

A total of 78 patients were screened for eligibility, of whom 60 met the inclusion criteria and were included in the study, with 30 patients in each group. Eighteen patients were excluded due to incomplete clinical data or presence of confounding conditions. Doppler ultrasound measurements demonstrated high intra-observer reproducibility, with an intraclass correlation coefficient greater than 0.85. Serum ADA assays showed consistent results with minimal inter-assay variability (< 5%). Representative Doppler spectral .......

Discussion

The accuracy of this protocol relies primarily on two steps: standardized Doppler ultrasonography acquisition and precise ADA quantification. In Doppler imaging, the most critical factors are correct probe placement, maintaining a consistent angle of insonation (≤ 60°), and sampling the same segment of the superior thyroid artery (STA) in all participants. Incorrect angle correction or sampling from different arterial branches can markedly alter PSV and RI measurements. Similarly, proper fasting state and rest.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
ADA (Adenosine Deaminase) Kinetic UV Assay Kit	Tulip Diagnostics		Kinetic UV method to quantify ADA (U/L)
Anti-Thyroglobulin Antibody (TgAb) Kit	Roche Diagnostics		Hashimoto’s hyperthyroidism marker
Anti-TPO Antibody Assay Kit	Roche Diagnostics		Used to identify Hashimoto’s thyroiditis
Automated Chemistry Analyzer	Beckman Coulter		For ADA testing (if run on chemistry platform)
Chemiluminescent Immunoassay Analyzer	Roche Diagnostics		Used for TSH, FT3, FT4 measurements
Methimazole tablets	Abbott		Antithyroid medication, 10–30 mg/day dosing per protocol
SPSS Statistical Software	IBM		Used for statistical analysis (SPSS v25)
TRAb Assay Kit	Roche Diagnostics		For diagnosis of Graves’ disease
Ultrasound Machine with Color Doppler	GE Healthcare		Used for thyroid Doppler evaluation, (LOGIQ series)